Back when Leo Fender was making his first amplifiers, he set the input impedance of jack one at 1 Megaohm (1M), a design that did not change through the tweed, blonde, brownface, blackface, or silverface eras of Fender amps. Fender guitars, being made for Fender amps, sound good when they are plugged directly into devices with 1M of input impedance.
That created a small problem for Andy and I as we were working on the band’s 1958(ish) Fender 1000 pedal steel guitar. The guitar, which we have documented previously, has its original 8-string Jazzmaster-style pickup. When Fender designed that pickup, it was intended to be paired up with their new tweed Bassman and Twin models – both sporting 1M input impedance. Andy’s pedal steel rig was not loading the steel guitar’s pickup correctly, leading to some unwanted dullness as he backed off the volume, and a distorted sizzling sound when he plugged into our Leslie speaker directly. Andy’s Goodrich volume pedal used a 500 Kiloohm (500K) potentiometer (pot), so the pickup was seeing 500K or less impedance, depending on where his volume pedal was set.